As noted, if they really want it, they will take it. Thing is, these days it's probably more profitable to take something more modern from the lot instead of an uncommon vintage car. I've driven my 73 vert 30K miles in the last 20 years to shows and events throughout NY, Vermont, Pa, Ohio, even to Nashville for the 40th in 2004 when vintage stangs were in a really hot market and although theft was a concern, the more serious problem was finding a safe parking spot where it has the best chance of not being dinged / scratched / dented by some uncaring (or intentional) jerk who parks 6 inches away and slams their door / suitcase / whatever into your car because they can.